Method and machine for chamfering gears



Feb. 20, 1945. J. E. GLEASON 2,369,963

METHOD AND MACHINE FOR CHAMFERING GEARS Original Filed Oct. 7, 1938 2 SheetsPSheet 1 IN VENTOR JAMES E. GLEHSON av /ZT T0 RNE Y Feb. 20, 1945. J GLEASQN 2,369,963

METHOD AND MACHINE FOR CHAMFERING GEARS Original Filed Oct. 7, 1938 2 Sheets-Sheet 2 JAMEs 1 GLEfiSdN TTOPNE Y Patented Feb. 20, 1945 METHOD AND MACHINE FOR cmmnnmo GEARS James E. Gleason, Rochester, N; Y., auignor to Gleason Works, Rochester, N. Y., a corporation of New York Original application October 7, 1938, Serial No.

233,805, now Patent No. 2,248,168, dated July 8,

1941, Serial No. 393,206

, (c1. sic-1.4)

Claims.

The present invention relates to the chamfering of gears and particularly to the chamfering of spiral bevel and hypoid pinions.

In spiral bevel and hypoid gears and pinions, opposite side surfaces of the teeth form acute angular corners with opposite end surfaces of the teeth, the concave side surfaces forming acute angles with the outer end faces of the teeth and the convex side surfaces forming acute angles with ,the inner end faces of the teeth. If these acute angular corners are not removed, they are liable to break off when the gears or pinions are in use and may get in between the teeth, causing noise, wear and often serious damage. For this reason, it is customary to chamfer the opposite sides of the teeth of spiral bevel and hypoid gears and pinions at the opposite ends thereof before the gears ur pinions are put into use. Machines have been devised for chamfering the teeth of spiral bevel and hypoid gears during the cutting of the teeth of the gears but, heretofore, the chamfering cf the teeth of spiral bevel and hypoid pinions has been done either by hand or on special chamfering machines in which only a single tooth or a single end of a tooth is chamfered at a time and the pinion has to be indexed from tooth to tooth to permit all of its teeth to be chamfered.

The primary object of the invention is to provide a method and apparatus for chamfering pinions which will be simple, cheap and extreme- 13' fast.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims;

The invention includes a novel tool, a novel method and a novel machine. The present application is directed to the method and machine and is a division of my application Serial No. 233,805, filed October 7, 1938, now Patent No. 2,248,168, issued July 8, 1941, which covers the tool.

With the present invention, one end of all of the teeth of a pinion may be chamfered simultaneously and in a single stroke of a chamfering tool. The chamfering tool has the general shape of an internal gear and has the same number of teeth as there are teeth in the pinion to be chamfered. I

For chamfering the two ends of the teeth of the pinion, twoseparate tools are required, one of the tools being made to a pitch and a pitch diameter approximately that of the pinion at its large end, and the other tool being made of a pitch and pitch diameter corresponding approxi.

Divided and this application My 13,

mately to that of the pinion at its small end. Each chamfering tool is adapted to have a telescoping relation with the teeth of the pinion during chamfering. Each is mounted coaxially of the pinion and-is moved axially relative to the pinion to effect the chambering operation. The tool for chamfering the large ends of the pinion teeth is preferably moved from the large end of the pinion inwardly, while the tool for chamfering the small ends of the pinion teeth preferably moves from the small end of the pinion inwardly. In the preferred embodiment of the invention, the teeth of each chamfering tool are made with profiles complementary to the profiles of the tooth surfaces to be chamfered so that the chamferlng operation removes a uniform amount of stock from the tooth over its whole height. The teeth of the chamfering tool are made, however, of slightly less width than the tooth spaces of the pinion so that they will clear those sides of the teeth of the pinion which do not require to be chamfered. Thetools are moreover made preferably with teeth inclined to the axis of the tool, that is, the tools have preferably the form of internal helical gears. In this way, cutting clearance will be provided back of the cutting edges of the teeth of the tools.

In the drawings,

Fig. 1 is a vertical sectional view illustrating more or less diagrammatically the construction and operation of a chamfering machine constructed according to one embodiment of this invention;

Fig. 2 is an end view of one of the chamfering tools;

Figs. 3 and 4 are a developed sectional view and a transverse sectional view, respectively, illustrating the chamfering process of' this invention;

Fig. 5 is a detail sectional View, showing the mechanism for clamping one of the work centers;

and

Fig. 6 is a fragmentary detail view of the work rest of the machine.

The machine illustrated in the drawings is shown set up to chamfer teeth of a spiral bevel or hypoid pinion P. Such a pinion is of generally conical shape and has longitudinally curved teeth T, (Fig. 3), whose concave sides i0 normally form acute angles with the outer end surfaces ll of the teeth and whose convex side surfaces It normally form acute angles with the inner end faces i3 of the teeth. To remove the acute angular corners l5 and It thus formed at opposite ends of the teeth is the purpose of the present invention.

pitch diameter approximately .that of the pitch large end and the of'theteethofthepinionatthesmall end. or contourof the teeth of one moreover, complementary to the profile uroftheteethofthe pinionatits the profile shape or contour of teeth of the other tool is complementary to profile shape or contour of the teeth of the rrggggg pitch or the teeth T of the pinion at the large ends of the teeth although the teeth 20 of the tool may be made of slightly less thickness than th'etooth spaces of the pinion so that the noncutting sides of the tool will readily clear those sides of the teeth of the pinion which require no chamfering. The tool has side-cutting edges formed at the .Iuncture of the side faces '2! 'of its teeth and the front faces 24 thereof. The sides II are inclined to the axis 23 of the tool to provide clearance hack of the cutting edges. The sides 22 of the teeth are non-cutting sides and may extend in the direction of the axis of the tool or be inclined thereto. They do not have to be given a profile shape but such a shape may be provided for convenience to insure complete clearance between the non-cutting side 22 and the adjacent tooth surface of the pinion. Preferably the sides 22 are shaped and made to extend longitudinally parallel to the sides 2|. The tool has then the form of an internal helical sear and its teeth may readily be cut on a Fellows-type gear shaper in a single operation.

The tool C" has cutting edges formed at the limcture of the sides 28 of its teeth 21 and the front faces 2: thereof. The sides 28 of the teeth of the cutter C are non-cutting sides. In the drawings, the tools are shown as sharpened so that the front faces 24 and 28, respectively, of their teeth lie in planes perpendicular to the axes of the tools. The individual teeth may, however, be sharpened with a side rake or with a hook to increase the cutting action if desired.

In use, the two cutting tools C and C are moimted to be co-axial of the pinion P whose teeth are to be chamfered. In the machine illustrated, the two tools are secured to rams It and SI, respectively, which are mounted to reciprocate toward and from one another on a dovetailed guide-way Ii which is formed on the under surface of an arm 32 which is inte ral with the frame I of the machine. Each tool may be becuredtoitsraminanysuitahlemannenasby supports 31 and 31'. The adjacent ends of these supports project through openings formed in the means of screws (not shown), which pass through arcuate slots 80 formed-in the tool and which thread into the rams.

Integral with the frame 38 or secured thereto in any suitable manner are a pair of guides or rams 3t and Two centers ll and 3. for supporting the pinion P, which is to be chamfered, are slidably mounted in these supports I1 and 31', respectively; Coil-springs denoted at It and 38, respectively, are provided for seating the centers against opposite ends of the work and the two centers may be moved into or retracted from operative position by segmental gears 4| and 40, respectively, which mesh with rack teeth 4| and 4|, respectively, that are formed on the v centers.

ried by arms and 45, respectively, which are pivotally connected to arms 46 and 4|, respec- 1 tively, that are keyed or'otherwise secured to the shafts on which the segments 40 and 4|, respectively, are fastened.

. The machine illustrated is of the horizontal type, that is, it is intended to operate with the work in horizontal position. For this reason, it is necessary to provide some temporary support for the work until. the centers as and II are in operative position. To this end, an arm or rest 50 is provided (Figs. 1 and 6). This rest has spaced sockets or recesses ll of V-shape to receive the shank of the pinion P and it is provided with a stop 48 against which the back- 40 cone of the pinion may be seated to determine the axial position of the pinion.

operative position and hold the pinion, the arm or rest ill is dropped out of the way. For this purpose, a face-cam 52 is provided. This cam is secured to the shaft 43 and engages a roller or follower that is carried by a rod 53 which is pivotally connected at 54 to the arm II. The arm 50 is itself pivotally mounted at 54 on the frame of the machine.

When the centers 38 and II have enga ed the pinion P, they are clamped or locked in engaging position. For this purpose, clamping blocks (Fig. 5) are provided. There are two blocks II for each center. The blocks are formed with arcuate clamping surfaces as indicated at it to engage the periphery of the center. The pair of blocks of each set are mounted for sliding movement on a rod or pin 61. A lever ll, that is bifurcated at its upper end, is pivotally connected to the head 58 of this rod by a pin 00. The ears CI of each lever 58 are formed with cam surfaces 62 which are adapted to engage the adjacent end face of one of the blocks so that when the lever BI is moved in one direction, the blocks It are forced together to clamp the center with which they are associated. When the lever is moved in the opposite direction, the center is released. Each lever 58 carries a roller or follower 65 at its lower end which engages the periphery of a cam 66. The two cams it are secured in any suitable manner to the shaft 43.

When the centers 38 and Iii have been moved into engagement with the pinion P to be chamfered and have been clamped in engaging position and when the rest or support 50 has been swung down out of operating position, the two rams 30 and 30' are moved toward one another to move the chamfering tools C and C axially and effect the chamfering operation at opposite ends of the teeth of the pinion P. The rams are operated from cams I and respectively. These cams are secured to the shaft 43. They are operatively connected with the rams 30 and 30 by levers H and 1|, respectively. These levers are pivotally mounted at their lower ends on the frame 33 of the machine by means of pins 12 and I2, respectively, and they are pivotally connected at their upper ends to the rams 30 and 30', respectively, by means of pins 13 and 13, respectively. The two levers carry rollers or followers I4 and 14', respectively, intermediate their ends which engage the tracks of the two cams Ill and 10'. For a shank pinion, such as shown in Fig. 1 of the drawings, the tool C will be required to travel a greater distance than the tool C in order to effect the chamfering operation and the track of the cam 10 will be formed accordingly, as shown, to give this greater travel.

It is necessary, of course, to position th teeth of the pinion relative to the cutting teeth of the tools so that in their strokes, the tools will effect the chamfering operation. For this purpose, a gauging finger 15 may be provided. This finger is mounted in an arm 16 that is pivotally secured by means of the pm 11 to the frame of the machine. It is intended to be engaged with a tooth space of the pinion P. It may be swung up out of the way manually to permit removal of a chamfered pinion and positioning of a new workpiece. A coil sprin 18 that is housed in the arm l5 serves to resiliently urge the finger 15 into gauging position.

The shaft 43 may be driven from a motor or other suitable source of power (not shown) through gearing which includes the bevel gear 88 that is fastened to the shaft.

In use, a pair of tools C and C are selected which are suitable for chamfering the opposite ends of the teeth of the gear which is to be chamfered and these tools are secured to the rams and 30. When the machine is stopped, it stops with the arm 50 in raised position and the rams 30 and 30' and the centers 38 and 38 retracted from operative position; To chamfer a pinion, the operator lays the pinion ,on the arm or rest 50. He then engages the finger 15 in a tooth space of the pinion P to properly position the teeth of the pinion with reference to the teeth of the chamfering tools. When this has been done, the operator starts the machine. This causes the shaft 43 to be driven through the gear 88. As the shaft 43 rotates, the center 38' is first brought up into operative position by action of the cam 42 through the segment 40 and the rack 4!. This center forces the pinion P against the shoulder 49 of the rest 58 to position the pinion axially and then the center is positively seated by the spring 39. Then the center 38 is brought into engagement with the opposite end of the pinion by operation of the cam 42, segment 40 and rack 4| and is seated by action of the spring 39. The centers are then clamped by action of the cams 66 through the medium of the levers 58 and the clamping blocks 55. Then, as the shaft 43 continues to rotate, the cam 52 operating through the rod 53 withdraws the rest or support 50 from operative position and the pinion remains suspended between the centers 38 and 38'. The

rams 30 and 30' now move toward one another under actuation of the cams l0 and 10'. When the teeth of the tools C and 0' come into engagement with the teeth of'the pinions, they clip the corners l5 and I6, respectively, off the opposite ends of these teeth, thus effecting the desired chamfering operation. As soon as the corners have been clipped off of the teeth of the pinion, the rams 30 and 30' reverse under actuation of the cams 10 and I0 and the tools C and C are retracted to the positions shown in Fig. 1. Then the cams 66 operate to release the centers 38 and 38. Following this, the cam 52 operates to move the rest or support 50 up into operative position again and then the cams 42 and 42' operate to retract the centers 38 and 38' from engaging position. The cycle of operation of the machine is completed and the operator can remove the chamfered pinion from the machine and substitute anotherifi its place.

The correct angular relation between the teeth of the chamfering tools and the teeth of the pinion is illustrated clearly in Figs. 3 and 4. It is such that when the tools are moved axially they will take off the desired amount of stock from the ends of the pinion teeth. The cutting edges of the teeth of the chamfering tool are denoted at in Fig. 4 while the sides of the pinion teeth, which are to be chamfered, are denoted at It]. As the tool C moves axially forward it will clip ofi the stock between the edges 85 and the sides to of all the teeth simultaneously, removing the corners denoted at I5 in Fig. 3. As the tool C moves axially rearwardly, it will clip off all the corners l6. Thus the corners at one end of all of the teeth of the pinion are removed simultaneously and in one cutting stroke of a chamfering tool.

In the preferred arrangement, as described, the two tools C and C move from opposite ends of the pinion simultaneously to chamfer the opposite ends of the teeth and thereby the cutting thrusts of the two tools are balanced one by the other. It will be obvious, however, that the two tools may cut alternately if desired.

While the invention has been described particularly in connection with the chamfering of the teeth of spiral bevel and hypoid pinions, it will be obvious that the invention may be applied also to the chamfering of the teeth of skew bevel gears and of helical spur gears, that is, to the chamfering of any gears whose teeth are inclined to the axis of the gear. Further than this, it will be obvious, also, that the invention may be applied to the chamfering of the teeth of helical internal gears by using a tool of external spur gear form having cutting teeth extending either in the direction of its axis or teeth with a different inclination to its axis than the teeth of the internal gear to be chamfered. The chamfering is here effected, as in the embodiment of the invention illustrated, by axial reciprocation of the chamfering tool.

In general it may be said that while the invention has been illustrated in connection with a particular embodiment thereof, it is capable of still further modification and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. The method or chamfering an already toothed gear that has side tooth surfaces which are longitudinally inclined to planes containing its axis and which form acute angular corners with the ends of its teeth, which comprises employing a tool that has a plurality oi circularly arranged cutting teeth whose circular pitch is approximately the same as the circular pitch or the gear, positioning said tool so that its cutting teeth are in axial alignment with the acute angu lar corners oi the teeth of the gear and axially reciprocating the tool relative to the gear while both the tool and gear are stationary on their axes.

2. The method of chamfering an already toothed gear that has side tooth surfaces which are longitudinally inclined to planes containing its axis and which form acute angular corners with the ends of its teeth, which comprises employing a tool that has a plurality of circularly arranged cutting teeth which are approximately complementary in profile shape to the profile shape of the teeth of the gear and whose circular pitch is approximately the same as the circular pitch of the gear, positioning said tool so that its cutting teeth are in axial alignment with the acute angular corners of the teeth of the gear and axially reciprocating the tool relative to the gear while both the tool and gear are stationary on their axes.

3. The method of chamfering an already toothed gear that has side tooth surfaces which are longitudinally inclined to planes containing its axis and which form acute angular corners with the ends of its teeth, which comprises employing a tool that has a. plurality of internally arranged cutting teeth of approximately the same circular pitch as the circular pitch of the teeth of the gear to be chamfered and which is adapted to completely encircle the gear, positioning the tool so that its cutting teeth are in axial alignment with the acute angular comers of the teeth of the gear and axially reciprocating the tool relative to the gear while both the tool and gear are stationary on their axes.

4. The method of chamferlng an already toothed gear that has side tooth surfaces which are longitudinally inclined to planes containing its axis and which form acute angular corners with the ends of its teeth, which comprises employing a tool that has a plurality of internally arranged cutting teeth which are of approximately the same circular pitch as the circular.

pitch of the teeth of the gear to be chamfered and which are approximately complementary in profile shape to the profile shape of the teeth of said gear, positioning the tool so that its cutting teeth are in axial alignment with the acute angular corners of the gear, and axially reciprocating the tool relative to the gear while both the tool and gear are stationary on their axes.

5. Apparatus for chamfering tapered gears that have side tooth surfaces which are longitudinally inclined to planes containing their axes comprising a work support, a pair of tools, one

of which has a plurality of circularly arranged v cutting teeth whose circular pitch and pitch diameter is approximately the same as the circular pitch and pitch diameter of the gear to be chamfered at its small end and the other of which has a plurality of circularly arranged cutting teeth whose circular pitch and pitch diameter is approximatelythesameasthecircularpitchand aseaees pitch diameter of the gear to be chamiered at its large end. means for positioning the work between the two tools in axial alignment therewith, and means for reciprocating the work axially relative to the tools.

6. Apparatus for chamfering tapered gears that have side tooth surfaces which are longitudinally inclined to planes containing their axes, comprising a work support, a pair of tools, each of which is of internal gear form and has a plurality of cutting teeth equal in number to the number of teeth of the gear to be chamfered, one of the tools being adapted to completely encircle the small end of the gear and the other tool being adapted to completely encircle the large end of the gear, means for positioning the work between the two tools in axial alignment therewith, and means for reciprocating the work axially relative to the tools.

7. Apparatus for chamfering a tapered gear that has side tooth surfaces which are longitudinally inclined to planes containing its axis, comprising a work support, a pair of tools, whose side tooth surfaces have a different longitudinal inclination to planes containing the tool axis from the longitudinal inclination of the side tooth surfaces of the gear to planes containing the axis of the gear and each of which is of internal gear form and has a plurality of cutting teeth equal in number to the number of teeth of the gear to be chamfered. one of the tools being adapted to completely encircle the small end of the gear and the other tool being adapted to completely encircle the large end of the gear, means for positioning the work between the two tools in axial alignment therewith, and means for simultaneously moving the two tools inwardly toward one another from op. posite ends of the gear toward the center thereof.

8. Apparatus for chamfering a gear that has side tooth surfaces which are longitudinally inclined to planes containing its axis, and which form acute angular corners with the ends of these teeth, comprising a work support, a pair of tools of gear form, each of which has tooth surfaces that are differently inclined longitudinally to axial planes of the tool from the longitudinal inclination of the tooth surfaces of the gear to axial planes of the gear and each of which has a number of cutting teeth equal to the number of teeth of the gear to be chamfered, means for positioning the work between the two tools with the cutting teeth of the tools in axial alignment with the acute angular corners or the teeth of the work, and means for simultaneously moving the two tools from opposite ends of the gear inwardly toward one another.

9. Apparatus for chamfering gears that have side tooth surfaces which are longitudinally inclined to planes containing their axes, and which form acute angular corners with the ends of their teeth, comprising a work support, a pair of tools, each of which has a plurality of cutting teeth which are diiferently inclined to axial planes of the tool from the inclination of the tooth surfaces of the gear to axial planes of the gear, the cutting teeth of each tool being of approximately the same circular pitch as and of approximately complementary profile shape to the teeth of the gear to be chamfered, means for positioning 'the tools at opposite ends of the gear with the cutting teeth of the tools in axial alignment with the acute angular corners of the teeth of the work, and means for reciprocating the gear relative to the tools.

10. The method of chamfering a tapered gear that has side tooth surfaces which are longitudinally inclined to planes containing the axis of the gear which comprises employing a tool that has a plurality of circularly arranged internally projecting cutting teeth which are equal in number to the number of teeth of the gear to be chamfered and which are arranged at approximately the same circular pitch as the circular pitch at one end of the gear to be chamfered, and positioning said tool opposite said end of the gear in axial alignment with the gear, and effecting relative axial movement between the tool and gear.

11. The method of chamfering a gear which has side tooth surfaces that are longitudinally inclined to planes containing its axis and that form acute angular corners with the ends of its teeth, which comprises employing a tool that has a plurality of circularly arranged, internally projecting teeth, each of which is inclined longitudinally to a plane containing the axis of the tool at a different angle from the angle of longitudinal inclination of the side tooth surfaces of the gear to the axis of the gear, the circular pitch of the teeth of the tool being approximately the same as the circular pitch of the teeth of the gear to be chamfered, positioning the tool so that its cutting teeth are in axial alignment with the acute angular corners of the teeth of the gear, and eflecting relative axial movement between the tool and gear while both the tool and gear are stationary on their axes.

12. The method of chamfering a tapered gear that has side tooth surfaces which are longitudinally inclined to planes containing its axis and which form acute angular corners with the ends of its teeth which comprises employing a pair of tools, each of which has a plurality of internally arranged cutting teeth, one of which has its teeth spaced at approximately the same circular pitch as the circular pitch of the teeth of the gear to be chamfered at the small end of the teeth of said gear, and the other of which has its teeth spaced at approximately the same circular pitch as the circular pitch of the gear to be chamfered at the large end of said gear and each of which has its teeth differently inclined longitudinally to planes containing the axis of the tool from the longitudinal inclination of the tooth surfaces of the gear to axial planes of the gear, positioning said tools so that their cutting teeth are in axial alignment with the acute angular corners of the teeth of the gear at opposite ends thereof, and simultaneously moving said tools axially from the ends of the gear toward the longitudinal center of its face while both the tools and gear are stationary on their axes.

13. The method of chamfering a gear that has side tooth surfaces which are longitudinally inclined to planes containing its axis and which form acute angular corners with the ends of its teeth, which comprises employing a tool that has a plurality of circularly arranged cutting teeth which are approximately complementary in profile shape to the profile shape of the teeth of the gear and whose circular pitch is approximately the same as the circular pitch of the gear but whose teeth have an inclination to planes containing its axis that is different from the longitudinal inclination of the side surfaces of the teeth of the gear to axial planes of the gear, positioning said tool so that its cutting teeth are in axial alignment with the acute angular corners of the teeth of the gear, and axially reciprocat ing the tool relative to the gear while both the tool and gear are stationary on their axes.

14. The method of chamfering a gear which has side tooth surfaces that are longitudinally inclined to planes containing its axis and that form acute angular corners with the ends of its teeth, which comprises employing a tool that has a plurality of internally arranged cutting teeth which have different longitudinal inclination to planes containing the axis of the tool than the tooth surfaces of the gear have to axial planes of the gear but which are of approximately the same circular pitch as the circular pitch of the gear and which is adapted to completely encircle the gear, positioning the tool so that its cutting teeth are in axial alignment with the acute angular corners of the teeth of the gear, and effecting a relative reciprocating movement between the tool and gear axially of the tool while both the tool and gear are stationary on their axes.

15. The method of chamfering an already toothed tapered gear which has side tooth surfaces that form acute angular corners with one end of its teeth, which comprises employing a tool that has a plurality of internally-projecting, circularly-arranged cutting teeth whose circular pitch and pitch diameter is approximately the same as the circular pitch and pitch diameter of the work at that end oithe teeth of the work which have said acute angular corners, positioning said tool so that its cutting .teeth are in axial alignment with said acute angular corners, and axially moving the tool relative to the work while both the tool and work are stationary on their axes.

JAMES E. GLEASON. 

